Patent GB-592587-A (GB)
Title: Process and apparatus for dialyzing solutions
IPC: B01D63/00
Filed: 1944-07-04
Abstract: A dialyzing apparatus comprises, in combination, a chamber, a multiplicity of tubular membranes disposed therein, means to pass the solution to be dialyzed into contact with one surface of all the tubes in such a manner that each portion of said solution contacts the surface of one tube only, and means to pass another liquid into contact with the other surface of the tubes.  The apparatus comprises a vertical closed chamber 10, having headers 15 and 16, positioned inside adjacent the ends, and provided with a plurality of holes into which are threaded short sections of pipe 17 to <PICT:0592587/III/1> which the dialyzing tubes 18 are anchored.  The tubes 18 may be disposed and arranged within the chamber in any desired manner provided that their longitudinal surfaces do not contact one another. The dialyzate (i.e., the solution to be dialyzed) can be introduced, intermittently or continuously, into the lower section 25, pass upwards through tubes 18 and fill section 27 until it overflows through outlet 28.  The diffusate (i.e., the solution of the material which diffuses through the membrane during dialysis) may be introduced into chamber 29 through pipe 30 and be removed through pipe 31.  The dialyzate may be caused to pass either inside or outside tubes 18 which together with the chamber 10, may alternatively be disposed in a horizontal plane.  Another embodiment comprises a number of multiwalled dialyzing tubes each of which consists of an inner tube surrounded by a tube of larger diameter, and, if necessary supported externally by means of a closely fitting tube made of an open fabric either of woven, knitted or braided construction.  The tubes may be supported between and positioned by means of double headers, leaving an air space between the co-axial tubes, in which case the front and back walls of the central section of chamber 10 are omitted in order that air may be blown over the external surfaces of the outer tubes.  In both embodiments the liquids may both flow upward or downward in the same direction instead of flowing counter currently.  The apparatus is adapted for dialyzing organic and inorganic substances from organic or aqueous solutions, and in particular for the separation of glycerine, butylene, glycol, citric acid, sugar and inorganic salts from their aqueous solutions.  For treating aqueous solutions the tubes may be formed of any hydrophillic film-forming material such as parchment paper, leather waste as sold under the Registered Trade Marks "Brechteen" and "Naturin," and non-fibrous cellulosic materials.  For the treatment of aqueous fluid compositions where it is desired to separate water or water miscible organic compounds from inorganic or organic substances (liquid or solid), it is preferable to employ a hydrophillic cellulosic tube such as are formed of a regenerated cellulose or cellulose hydrate, alkali-soluble water insoluble cellulose ethers, gelatine (insolubilised), casein, alginates and similar film-forming hydrophillic plastic materials.  To separate an organic liquid from water or organic compounds of a different type, there may be used tubes formed of hydrophobic colloidal-materials such as:-polyvinyl resins, methyl methacrylate resins, chloroprene, nylon and chlorinated rubber; or of organic solvent-soluble cellulose derivatives such as cellulose ester, cellulose ether, a mixed cellulose ether, a mixed ether-ester of cellulose, as well as tubes formed of two or more resins or of two or more cellulose derivatives, also tubes formed from a mixture of a hydrophobic resin with a hydrophobic cellulose derivative.  The tubular membranes are all preferably used in the swollen state, i.e., while they are saturated with water or the organic liquid which it is desired to evaporate through the tube.  Specification 592,588 is referred to.